I mean, Jefferson's stats are really not good, he isn't projectable, he doesn't even K a batter per inning or have a 2:1 K:BB ratio, I don't believe his potential is anywhere close to a number 1 SP personally. I don't entirely know what the progress is, unless getting that ERA below 5 is a major milestone...

Look, I understand your point, but considering his ERA was pushing 8.5 in late May, it shows just how well he's pitched to bring it under 5. He's got 5 consecutive quality starts, so yes he's making progress. Keep in mind that often times the big kids -- he's 6'7" 260 -- take a while to figure it out mechanically. And if indeed that is what is happening w/this huge hard throwing 19 year old then his ceiling just went up.